BIODIESEL SYNTHESIS FROM MUSTARD OIL (BRASSICA NIGRA OXIDE-CALCIUM
Transcript of BIODIESEL SYNTHESIS FROM MUSTARD OIL (BRASSICA NIGRA OXIDE-CALCIUM
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BIODIESEL SYNTHESIS FROM MUSTARD OIL (BRASSICA NIGRA) USING CALCIUM
OXIDE-CALCIUM ALUMINATE CATALYST DEVELOPED FROM DUCK EGGSHELL
R.Chakraborty, S.Bepari#
Department of Chemical Engineering, Jadavpur University, Kolkata 700032, India ,Tel.:
09831259201;
# Department of Chemical Engineering, Jadavpur University, Kolkata 700032, India,
___________________________________________________________________________
Abstract
An efficient and inexpensive calcium oxide-calcium aluminate solid base catalyst has
been developed for biodiesel synthesis from mustard oil (MO) of Indian origin (Brassica
Nigra). The active metal precursor Ca (OH) 2 of the catalyst has been economically derived
through calcination of waste duck eggshell and the high activity supported catalyst has been
prepared through co-precipitation method. X-ray diffraction (XRD), scanning electron
microscope (SEM), low temperature N2 adsorption-desorption (BET) and Mercury Intrusion
Porosimetry (MIP) studies demonstrate the existence of CaO and calcium aluminate
crystalline phases with rod like macroporous particles having specific surface area of 2.909
m2/g, pore volume of 0.55 cc/g and a basicity of 12.6 mmol HCl/g catalyst. The high catalytic
activity has been demonstrated through transesterification of MO for synthesis of biodiesel. A
three factor-three level face centred central composite design (FCCD) has been used to
determine the effects of process parameters on fatty acid methyl ester (FAME) yield. Optimal
parametric values were CaO loading of 30 wt.%, calcination temperature of 990 °C and 3.82
wt.% catalyst concentration which resulted a remarkably high (i.e. maximum 99.58%) FAME
yield evaluated using response surface methodology (RSM). The fuel properties of prepared
biodiesel have been found to comply with ASTM/ EN standards.
Keywords: calcium oxide-calcium aluminate catalyst, waste duck eggshell, Indian mustard
oil, biodiesel, RSM optimization
__________________________________________________________________________
Corresponding Author, Tel.: 09831259201; (Dr. R. Chakraborty)
1 Introduction
Due to the increased environmental concerns about pollution, researches on biodiesel
as alternative fuel have gained much impetus in recent years [1-3].Mustard oil (MO) is the
third largest edible oil produced in the world after Soybean oil and Palm oil. Hence, MO has
a great potential to be utilized as a cheap feedstock for biodiesel synthesis. Methanolysis of
wild mustard seed oil was carried out [4] through transesterification using sodium methoxide
as homogeneous catalyst. Reports have been made on biodiesel production from Brazilian
mustard oil (Brassica juncea L.) employing sodium methoxide with 94 wt.% yield [5] and
Ethiopian mustard oil (Brassica carinata) [6,7] with 99 wt.% yield using homogeneous KOH
catalysts. More recently, transesterification of spent mustard oil (Brassica campestris) was
investigated using homogeneous sulfuric acid (95%) followed by bubble washing [8].
However, use of homogeneous catalysts [9-12] has made biodiesel synthesis process
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complicated because of complexity in product purification besides having corrosion and
contamination problems. In order to overcome the demerits of homogeneous catalyst based
process, recently tremendous attention has been focussed on heterogeneous catalysts.
Many works have been reported on heterogeneous base catalysts viz. CaO,
Sr(NO3)2/ZnO, KI/Al2O3, Na/NaOH/Al2O3, KF/MgO, ion-exchange resins etc. capable of
conducting transesterification reaction [13-18]. In all cases direct utilization of analytical
reagent grade chemicals have been attempted [19, 20] for catalyst preparation requiring high
cost. Investigations have been conducted to utilize wastes viz. chicken eggshell [21], oyster
shell [22], mud crab shell [23] and waste fish scale [24] as cheap resources for preparation of
low cost heterogeneous catalyst in biodiesel production. Complete conversion of sunflower
oil to biodiesel could be achieved using calcium oxide (CaO) in supercritical methanol at the
expense of high temperature (525 K) and high methanol/oil molar ratio [25].
Nevertheless, as CaO exists in the reaction mixture in a form of suspensoid due to its
poor mechanical strength, resulting in separation problems of catalyst from biodiesel
products; thus, supporting CaO onto carriers was found to improve the performance of CaO
catalysts [26-28].Transesterification of soybean oil with a CaO/mesoporous silica catalyst
rendered a maximum FAME yield of 95.2% but required considerably higher reaction time of
8 h [29]. In the past, Al2O3 supported CaO catalyst had been developed using reagent grade
chemicals for production of biodiesel from microalga‟s lipid [30] and palm oil [31-33]. But to
the best of our knowledge, no investigation has been reported for the economical preparation
of the Al2O3 supported calcium oxide-calcium aluminate heterogeneous catalyst utilizing
waste duck eggshell for synthesis of biodiesel from mustard oil (Brassica Nigra).
The present work, thus, aims at development, characterization and performance
evaluation of a calcium oxide-calcium aluminate solid catalyst utilizing waste duck eggshell
(instead of using reagent grade chemicals) as the cheap resource for the active metal
precursor. The efficacy of the prepared catalyst has been tested in transesterification of
mustard oil (Brassica Nigra) with methanol to obtain fuel grade biodiesel. Relationship
between fatty acid methyl ester (FAME) yield and process variables viz. CaO loading,
calcination temperature and catalyst concentration affecting transesterification of MO with
methanol has been established through a three factor-three level face centered central
composite design (FCCD) and optimal parametric values corresponding to maximum FAME
yield has been estimated using response surface methodology (RSM). The fuel quality of the
product biodiesel has also been evaluated.
2 Materials and Methods
2.1 Materials
Used frying mustard oil (Indian origin) and waste duck eggshells were collected from
local restaurants. All the chemicals used were of analytical reagent (AR) grade. Methanol
(>99% purity), aluminium nitrate nonahydrate [Al (NO3)3.9H2O], aqueous NH4OH solution,
anhydrous sodium sulphate [Na2SO4], acetone etc. were purchased from Merck.
2.2 Catalyst preparation
Duck eggshells were first washed with deionised water repeatedly to remove
impurities and then dried in hot air oven at 100°C for about 24 h. The dried shells were
ground to fine powder and calcined in a muffle furnace at 1000°C for 2 h to yield CaO to
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obtain the active precursor i.e. Ca(OH)2. The catalyst was prepared through co-precipitation
method. In the present study, aqueous solution of Al (NO3)3.9H2O and Ca (OH) 2 were first
prepared by dissolving Al (NO3)3.9H2O and CaO powder (obtained from duck eggshell
calcination) in deionised water respectively. Typically, 3 g of calcined eggshell powder and
27 g of Al (NO3)3.9H2O were added to 200 mL of water to prepare 10 wt.% CaO loading and
mixed vigorously using mechanical agitator under total reflux for 1 h at pH 10(maintained
through drop wise addition of aqueous NH4OH solution) to facilitate the precipitation of the
metal precursors from their respective aqueous solutions and aged for 24 h . Excess water
was removed using hot air oven at 100°C for 2 h. Subsequently, the dried precipitates were
finally calcined in muffle furnace over a temperature range from 500°C to 1000
°C to prepare
the Calcium oxide-calcium aluminate solid base catalyst.
2.3 Catalyst characterization
X-ray diffraction (XRD) patterns for each supported catalyst samples obtained by
calcining at temperature ranges between 500°C and 1000
°C were analyzed (Rigaku Miniflex
Co., Japan) using Cu-K source equipped with an Inel CPS 120 hemispherical detector. The
analysis was performed at 2 ranging from 20-80° at a scanning speed of 3
° min
-1. The
surface morphology of the catalyst particle was monitored using scanning electron
microscope (SEM) (JEOL ltd, JSM-6360). The specific surface area of the prepared catalyst
sample was measured by BET method using low temperature N2 adsorption-desorption
(Quantachrome make NOVA 4000e). The sample was tested for pore size distribution from
0-60000 PSI using Mercury Intrusion Porosimetry (MIP) method (Quantachrome make
Poremaster 60).In our study, the method of titration [34] was used to determine the basicity
of the catalyst.
2.4 Equipment
The laboratory scale experimental set-up of biodiesel synthesis consisted of a three
necked borosil flask (1 L capacity) employed as the batch reactor for carrying out
transesterification of MO. The flask was heated over a heating mantle provided with a PID
temperature controller to maintain isothermal condition corresponding to the set point for
biodiesel synthesis. The two necks of the flask were connected with two reflux condensers
and the reaction mixture was agitated by a centrally placed motorized stirrer during the
progress of reaction.
2.5 Transesterification reaction procedure
The physicochemical properties of the MO have been presented in Table 1.
Methanolysis of the MO was performed in the batch reactor at 700 rpm. Initially, pre-treated
MO (91 g, 100 mL) and proportional amount of prepared catalyst were added to the flask. In
all experimental runs, the mixture was stirred for few minutes to make oil-catalyst slurry and
heated to 70°C, followed by addition of methanol (methanol/oil ratio 0.30 (v/v)) and the
reaction was conducted for 4 h.
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Table 1 Properties of Mustard Oil (Indian Origin).
Property Value
Density, 15°C (g/ml) 0.91
Kinematic viscosity, 40°C (cSt) 42.3
Acid value (mg KOH/g) 0.2
Moisture content, wt.% 3-4
Transesterification reactions were conducted according to each design points (Table
2) and the results of the FAME yields were used as the response values in order to optimize
the process conditions.
Table 2 Experimental ranges and levels of the independent variables (process factors) for
response surface study.
Factors
Name
Units
-1 level
0 level
+1 level
LX CaO loading
Wt.%
30
40
50
CX
Catalyst
Concentration
Wt.% oil 1 3
5
CTX
Calcination
temperature
°C 800
900
1000
At the end of each batch, reaction mixture was equilibrated to room temperature and
transferred to a laboratory scale vacuum filter for solid catalyst separation. After filtration,
the filtrate was centrifuged at about 4000 rpm for 10 min for separation of the ester phase
from glycerol phase. Biodiesel was obtained as the top layer while glycerol at the bottom.
The biodiesel phase was then purified by carrying out distillation in a laboratory scale batch
vacuum distillation flask to recover unreacted methanol. The traces of alcohol were removed
by washing with hot distilled water followed by drying with anhydrous Na2SO4.
2.6 Yield, Purity and fuel properties of synthesized biodiesel
The FAME yield obtained through transesterification of MO was calculated as
follows:
)1(FAME
o
b
FAME pW
WY
The quantitative FAME content of biodiesel obtained through transesterification of
MO was determined by gas chromatography (GC). The GC apparatus (Perichrom
Instrumentation, PR-2100) fitted with a flame ionization detector (FID) employed a capillary
column (SGE E10, 25m × 0.53mm i.d. × 1.0 µm). Nitrogen was used as a carrier gas at a
flow rate of 2 mL/min. The oven temperature was initially held at 120°C for 3 min, increased
to 240°C at 5
°C
min
-1 and then held for 3 min. The injector and detector temperatures were
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250°C. FAME peaks were identified by comparison with the retention time of reference
standards with known double bond positions.
The important fuel properties of the prepared biodiesel have been tested as per ASTM
and EN standard methods.
2.7 Experimental design
A three-factor, three-level face centered central composite design (FCCD) has been
used (Table 3) to determine the optimal values of process parameters viz. CaO loading i.e.
catalyst precursor dosage (LX ), catalyst concentration ( CX ) and calcination temperature (
CTX ) influencing FAME yield (FAMEY ).
Table 3 Face centered central composite design (FCCD) layout for transesterification of MO.
Run Factor (LX ) Factor ( CX ) Factor ( CTX ) Response
CaO loading
(wt%)
Catalystconcentration
(wt.% oil)
Calcination
temperature (°C)
FAME Yield
%
1 -1 0 0 96.56
2 1 1 -1 75.23
3 0 0 -1 85.99
4 0 1 0 89.62
5 0 0 0 91.08
6 -1 1 1 99.5
7 0 -1 0 92.54
8 0 0 1 94.17
9 -1 1 -1 91.0
10 -1 -1 1 99.29
11 1 0 0 84.6
12 1 -1 -1 85.8
13 1 -1 1 93.17
14 1 1 1 86.21
15 -1 -1 -1 91.2
40
;10
LL
Xx
3;
2
CC
Xx
900;
100
CTCT
Xx
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A two factor interaction (2FI) response surface equation has been developed by using Design
Expert 8.0 software. The selected independent variables (viz.LX , CX and CTX ) each had
three levels; which were -1, 0 and +1. A total of 15 different combinations were chosen in
random order according to FCCD configuration for three factors. The experiments were
conducted in triplicate and the mean value of the response has been used in the statistical
analysis.
3. Results and discussion
3.1 Charaterization of the catalyst
Fig. 1(a)-1(f) shows the XRD patterns for the prepared catalyst samples developed
over a calcination temperature range from 500-1000°C.
Fig.1 Powder XRD patterns of developed catalyst obtained by calcining at various
temperature ranges (500-1000°C). [Characteristics peaks due to CaO ( ), Al (NO3)3 ( ),
Al2O3 ( ), Ca (OH)2 ( ) and calcium aluminate i.e. 12CaO-7Al2O3 ( ) ]
The small peaks seen in the figure do not correspond to the diffraction pattern of pure CaO
crystallite phase; these are identified as the mixture of calcium aluminate hydrate and/or
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alumina hydrate formed due to adsorbed water on the catalysts [35]. This can be attributed to
the fact that samples were open to atmosphere prior to and during the XRD measurements;
hence, resulting in the adsorption of water from air. It can be observed that, for calcination at
500°C the presence of CaO inhibited the sintering of Al2O3, which is evident from the
absence of clear diffraction pattern corresponding to a specific alumina crystallite phase and
this corroborates well with Baik and Moon [36]. Samples calcined below 800°C, resulted
some unconverted peaks of aluminium nitrate which can be seen from the Fig. 1(a)-1(c).
XRD patterns depicted clear and sharp peaks of CaO corresponding to calination temperature
of 800°C, similar to literature reported results [21]. Fig. 1(e)-1(f) shows reflection of peaks of
CaO and Al2O3 when the oven dried samples were calcined above 800°C conforming to
formation of Al2O3-supported CaO catalyst framework. However, a decrease in the CaO
peaks was observed with the corresponding appearance of calcium-aluminate crystalline
phase at higher calcination temperatures of 900°C and 1000
°C [37].
The morphology of representative catalyst sample was observed through SEM image
(Fig.2). The calcined sample (900°C) showed formation of interconnected (aggregated) rod
like particles .
Fig.2: SEM image of preapared catalyst obtained through calcination at 990°C
The SEM micrograph of the developed catalyst does not reveal the presence of CaO –
calcium aluminate segregated from the support, thus, indicating the uniform distribution of
the active phase on the Al2O3.
The specific surface area of the catalyst developed in the present study was
determined by Brunauer–Emmett–Teller (BET) method. Zabeti et.al [31] although developed
Al2O3 supported CaO catalyst from reagent grade chemicals using impregnation method for
synthesis of biodiesel from palm oil; but no BET data was reported. In our work, a specific
surface area (BETS ) of 2.909 m
2/ g was determined corresponding to 30 wt.% CaO loading
and 1000°C calcination temperature. Thus, in the present investigation, a significant
enhancement inBETS has been achieved compared to the case of unsupported-CaO (
BETS of
1.1 m2/ g) catalyst derived from direct calcination of waste chicken eggshell [21] and also
greater than ( BETS of 1.07 m2/ g) reported by Pant and Kunzru[37] for calcium aluminates
prepared from calcium carbonate.
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Fig.3a: Pore volume vs. relative pressure Fig.3b:Differential pore volume
of prepared catalyst vs. pore diameter of prepared catalyst
The shape of the isotherm (Fig.3(a)) depicting pore volume of the developed catalyst
as a function of relative pressure (P/P0) suggests that the developed catalyst is essentially
macroporous solid and the isotherm for this material can be ascribed to type II of the IUPAC
classification [38]. Point B, the beginning of the almost linear middle section of the isotherm,
usually specifies the stage at which monolayer coverage is complete and multilayer
adsorption about to begin. A pore volume of 0.55cc/g was determined. Fig. 3(b) indicates a
fairly normal peak distribution of macropores in the region above 4 µm pore size. The modal
pore size of the developed catalyst is determined as 0.8 µm which is large enough to allow
the entry of voluminous triglyceride and free fatty acid molecules in to the catalyst pores
ensuring efficient performance of the developed catalyst.
The basicity of the developed catalyst has been determined to be 12.6 mmol HCl/g
catalysts; this further ascertains the highly efficient characteristics of the catalyst.
The characteristics of the basic sites (Lewis base) of calcium aluminates-CaO are
most likely due to the presence of oxygen ions on the catalyst surface. The formation of
various types of oxygen ions on the surface renders an enhancement in the initiation reaction
by abstracting hydrogen ion from the methanol.
3.2 Statistical analysis
The RSM optimization [31] for biodiesel production based on central composite
design (CCD) considered only two factors. However, in the present work, RSM model based
on FCCD with three factors viz. CaO loading, calcination temperature and catalyst
concentration has been formulated to investigate the performance of the developed catalyst.
The experimental results depicting FAME yield (FAMEY ) as a function of process parameters
(factors) tabulated according to FCCD are shown in Table 3. It can be observed from the
analysis of variance (ANOVA) (Table 4), that a two factor interaction (2FI) model was
significant with a p-value (probability of error value) less than 0.0001 to predict the FAME
yield values. The significant model terms (for 95% confidence intervals) with p-values less
than 0.05 wereLX , CTX , CX and
LX CX ; whilst LX CTX and CTX CX were insignificant
terms as their p-values were greater than 0.100.
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Table 4 ANOVA results for FAME yield corresponding to Eq. 2
Source Sum of
squares
df Mean square F value p-value
Prob > F
Model 544.62 6 90.77 128.86 <0.0001
LX 276.05 1 276.05 391.88 <0.0001
CX 41.78 1 41.78 59.31 <0.0001
CTX 185.93 1 185.93 263.96 <0.0001
LX CX 38.46 1 38.46 54.59 <0.0001
LX CTX 0.39 1 0.39 0.55 0.4796
CX CTX 2.02 1 2.02 2.87 0.1288
Residual 5.64 8 0.70 - -
Cor. Total 550.26 14 - - -
In our analysis, a statistical „Model Fit Summary‟ confirmed the suitability of the 2FI
model (Eq. (2)) compared to linear or quadratic model (Table 5). Also, the “Pred-R Squared”
of 0.9330 for the 2FI model was in reasonable agreement with “Adj R-Squared” of 0.9821
implying that the 2FI model was the best model to represent the parametric effects on FAME
yield.
Table 5 Model Fit Summary of linear, 2FI and quadratic model developed in case of
FAME yield from MO.
Source Standard
deviation
R-Squared Adjusted R-
Squared
Predicted
R-Squared
Adeq.
precision
Linear 2.06 0.9155 0.8924 0.7963 21.870
2FI 0.84 0.9898 0.9821 0.9330 42.770
Quadratic 0.85 0.9934 0.9815 0.9059 35.216
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The final equation in terms of coded factors:
2
90.40 5.25 2.04 4.31 2.19 0.22 0.50 (2)
( 0.9898)
FAME L C C L C L CT C CTTY x x x x x x x x x
R
)1,,1( CTCL xxx
Eq.2 in coded factors indicates the effect of the variables on the response [32]. The
model suggested CaO loading (precursor dosage) as the most important factor with a negative
influence on FAME yield (FAMEY ). Calcination temperature became the second important
factor followed by catalyst concentration affectingFAMEY . Calcination temperature had
positive effect similar to [31], while CaO loading and catalyst concentration individually
rendered negative impact on FAMEY over the experimental range of parametric values. Higher
CaO loading might have resulted in poor dispersion of the active site over the support frame
work, and thus, resulted in less efficient catalyst. Higher catalyst concentrations possibly
have rendered a mixing problem between the liquid reactants and solid catalyst at the
prevailing stirring speed, which corroborates well with the findings of Yang and Xie [39].
The developed model equation has been validated using separate experimental results other
than those used for FCCD.
3.3 Influence of interaction effects
Among all the variables studied, the interaction effects between CaO loading and
catalyst concentration parameters have been found to have pronounced effect on FAME yield
as shown in Fig.4 (a).The figure indicates that the effect of CaO loading depends on the level
of catalyst concentration.
(a) (b) (c)
Fig.4 Influence of interaction effects on FAME yield:(a). CaO loading and catalyst
concentration,( b). catalyst concentration and calcination temperature,( c). CaO loading and
calcination temperature; factor‟s lowest level ( ) ; factor‟s highest level ( )
At higher level( ) of catalyst concentration, the FAME yield has been observed to depend
significantly on CaO loading; while at lower level( ) the dependence of FAME yield on CaO
loading is relatively less. It is evident from Fig. 4(b) that at lower level of calcination
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temperature the yield of FAME is relatively more dependent on catalyst concentration
compared to that at higher level. However, Fig. 4(c) reveals that, the effect of CaO loading on
biodiesel yield is practically independent (similar to [31]) of calcination temperature with
very small positive interaction between the parameters.
Fig.5 depicts the effects of interaction between CaO loading and catalyst
concentration on the predicted FAME yields (%) at the central value of calcination
temperature i.e. 900°C.At lower CaO loading, an increase in catalyst concentration does not
affect FAME yield appreciably. This possibly signifies that the heterogenous catalytic
reaction is not limited by surface reaction kinetics .At higher CaO loading, an increase in
catalyst concentration would significantly reduce the FAME yield .This indicates, a mass
transfer controlled reaction regime possibly due to a mixing problem between the solid
catalyst and liquid reactants at higher catalyst concentration.
Fig.5: Contour plots of the predicted FAME yields (%): CaO loading versus catalyst
concentration at a calcination temperature of 900°C
3.4 Optimal Process Conditions
The optimal process conditions viz. CaO loading of 30 wt.%, calcination temperature of
990°C and 3.82 wt.% catalyst concentration that corresponded to maximum (i.e. 99.58%)
biodiesel yield was determined through RSM . The biodiesel(FAME) yield obtained in the
present study is greater than that obtained applying CaO/Al2O3 catalyst (prepared from
reagent grade chemicals) on microalga‟s lipid [30] and palm oil [31,32] .Besides, the
biodiesel yield achieved in the present study is comparable with that obtained from Brssica
Carinata (Ethiopian mustard oil) using homogeneous KOH catalyst [6] and is greater than
that (94 wt%) obtained from Brssica juncea L.(Wild Brazilian mustard oil) using sodium
methoxide catalyst [5].
In order to ascertain the precision of the formulated 2FI model (Eq.2), a
transesterification reaction under the determined optimal operating conditions was carried out
in triplicate and the mean experimental value (99.001%) and predicted value (99.580%) differ
by less than 1.0 %. Thus, it can be concluded that the developed model possesses sufficient
accuracy to predict the FAME yields.
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3.5 Properties of the prepared biodiesel
The fuel properties of prepared biodiesel (Table 6) were found to comply with ASTM
/ EN standards.
Table 6. Properties of biodiesel synthesized from MO.
Property Specification Results Testing Method
Ester content %
(w/w)
96.5 min >99 EN 14103
Density (15 °C) 860-900 882 EN ISO 3675
Viscosity (40 °C )
mm2/s
3.5-5.0 4.1 EN ISO 3104
Cetane number (°C) 47 min 64 ASTM D6890
Cloud point (°C) - 16 ASTM D2500
Pour point (°C) - 12 ASTM D97
Cold filter plugging
point (°C)
- 9 EN 116
Sulphur, % m/m 0.05 max 0.04 ASTM 6751
Acid No. mg KOH/g 0.5 max 0.1 ASTM D6751-06
3.6 Catalyst reusability
The reusability study on the developed catalyst indicated repeated usability for about
15 times without major loss of activity in transesterification of MO. Before each reuse, the
used catalyst was washed with methanol and subsequently air dried at 110 °C. The catalyst
started losing activity slowly after being used for more than 5 times and became ineffective
after being used for more than 10 times. The catalyst deactivation was attributed to the
hydration of catalyst resulting from reaction with water (present in small amount in feed oil
and methanol). Catalyst used more than 10 times, when analyzed in XRD, displayed
characteristics peaks of Ca (OH) 2 indicating transformation of CaO due to hydration.
However, the catalyst can be regenerated through calcination at 990°C.
In order to obtain an idea of solid catalysts dissolution into reaction medium, FAME
fraction and glycerol fraction of each of the product samples were subjected to elemental
analysis using flame atomic absorption spectroscopy (Varian AA104) employing acetylene
flame. Calcium ion content of the final biodiesel product was found to be below 0.02 ppm
which is much less than 31 ppm [31] reported for similar catalyst. This confirms that there
was very negligible leaching of the active metal species in to the reaction medium, this could
further ascertain the chemical stability of the prepared catalyst.
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4. Conclusion
In the present study, a municipal solid waste i.e. duck eggshell has been utilized as a
cheap resource to develop an inexpensive Al2O3 supported heterogeneous base catalyst for
biodiesel synthesis through transesterification of Indian mustard oil (Brassica Nigra). The
catalyst developed through co-precipitation method, has demonstrated high efficacy for
transesterification reaction producing biodiesel conforming to the ASTM / EN standards fuel
quality with greater than 99% FAME yield. The optimal conditions of process parameters
have been determined for maximization of FAME yield using RSM through FCCD. The
developed statistical model equation can be used to predict the FAME yield at different
values of process variables over the parametric range considered in this study. The paper,
thus presents a comprehensive report for synthesis of green fuel through a cost effective
waste management avenue.
Nomenclature
AN Acid Number, mg KOH/g oil
FAMEY FAME yield, %
bW Weight of biodiesel, g
FAMEp Total wt. % of FAME in biodiesel, %
oW Weight of MO, g
LX Wt.% CaO loading
CX Catalyst concentration, wt.% oil
CTX Calcination temperature, °C
Lx Coded value of CaO loading
Cx Coded value of catalyst concentration
CTx Coded value of calcination temperature
References
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